Vapor forced engine

ABSTRACT

A vapor-driven piston-type engine having multiple stages that may be constructed as a single block or unit. Each stage has its own separate vapor power source and the fluids in each stage are different and have different heat/temperature characteristics such that the waste heat from one engine can be used to drive a succeeding engine.

This is a divisional of application Ser. No. 08/277,524 filed on Jul.19, 1994 now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a vapor-driven piston-type engineand in particular to a vapor-driven piston-type engine that has a firstfluid therein that receives heat from a heat source to vaporize thefluid and drive the piston engine and which includes therein a secondclosed fluid path in heat exchange relation with the first fluid path toincrease the efficiency of the engine. In a still further embodiment, aplurality of the efficient vapor-driven piston-type engines are coupledone to another in different closed circuits whereby the fluid in thefirst closed circuit in a second or subsequent vapor-driven piston-typeengine is heated by the first vapor-driven piston-type engine or by thefluid flowing through it.

2. Description of Related Art

A conventional vapor force piston device contains a vaporizable fluid,an evaporator for vaporizing the fluid, the vapor piston machine and aclosed circuit in which the evaporator and the vapor piston machine areinterposed for the transport of the fluid. Such a conventional vaporforce device of this sort may be a steam power plant which uses water asa fluid. The evaporator is the steam generator and the vapor machine isa steam engine with pistons or a steam turbine driving a currentgenerator.

However, water evaporates at 100° C. under atmospheric pressure. Inorder to obtain a good efficiency, over-heated or super-heated steam atan even far higher temperature is required. This implies that for theevaporation in the steam generator, high quality and quantities of fuelare required. It further implies that the device cannot work on heatalone at a relatively low temperature even though it may be available inlarge amounts. Thus the supplied energy is relatively expensive.

In U.S. Pat. No. 3,218,802 and issued in the name of D. R. Sawle, abinary vapor power plant includes a sulfur cycle consisting of a heatsource 10 which heats and vaporizes sulfur, a first stage sulfur heatengine 12 which converts the heat in the vapor into kinetic energy, anda heat exchanger 14 that receives the partially cooled sulfur andremoves the remainder of the heat. The heat exchanger 14 heats the fluidin conduits 37, 41, and 43 to convey steam to a second stage heat engine16. Similar systems have been employed at petrochemical plants that useethylene-oxide reactors. The reactors are cooled by a high temperature,low pressure fluid (diphyl fluid). This fluid is sent to a heatexchanger to produce the super-heated steam. The steam was used in asteam turbine to compress ethylene gas. This system has very difficultproblems to overcome since using sulfide, sulfur, phosphorus or evensodium is excluded because steel is hydrogen permeable and hydrogen withthe above materials will give severe problems. This is a very hightemperature device with saturated sulfur vapor at 1260° F.

In U.S. Pat. No. 4,070,862 issued to Doerner et al., a turbine in powerstation plants is provided with two different fluids such as water andH₂. One of the problems is the leakage from one turbine site to theother. The invention is a choice of two liquids where the second liquidhas a lower boiling point than the first liquid and returns the vaporcondensate (linkage) to the boiler. The two liquids have low pressurescompared to their temperatures at 800° F. with 34 PSIA and 450° C. at 51PSIA. Athough there are no efficiency figures stated in this patent, theuse of such high temperatures and low pressures must have a detrimentalinfluence on the overall efficiency of the turbine.

In U.S. Pat. No. 4,700,543 to Krieger et al., a plurality ofindependent, closed Rankine cycle power plants, each of which has avaporizer and is operated by serially applying a medium or lowtemperature source fluid to the vaporizers of the power plants forproducing heat-depleted source fluid. The heat-depleted source fluid isapplied to all of the preheaters in parallel. The power plants are shownto be turbines.

Thus, there is a significant need in the art for a vapor-drivenpiston-type engine that has high efficiency and which operates atrelatively low temperatures.

SUMMARY OF THE INVENTION

The present invention aims to remedy these disadvantages and to providea highly efficient vapor-force piston device whose operation isrelatively inexpensive and which, in a particular embodiment, enablespractical use to be made of temperature sources at a relatively lowtemperature, thus enabling the use of inexpensive fuels.

The results are achieved with the present invention because the fluidused in the machine is a fluid with an atmospheric evaporationtemperature lower than 50° C. and with such evaporation characteristicsthat even at a low temperature, high pressure vapor is obtained.Suitable fluids are, in particular, those fluids which are used incooling installations such as fluorohydrocarbons or an equivalentalternative. A very well-suited fluid, therefore, is 1,1-dichloro2,2,2-trifluoroethene.

According to a special embodiment of the invention, the evaporator is aheat exchanger having the above-mentioned fluid as a secondary fluid andanother liquid as the primary fluid. The heat exchanger may, in apractical sense, form the radiator of an explosion engine, such as anautomobile engine, whose coolant forms the primary fluid. Alternatively,the heat exchanger may be a device that exchanges heat between a hot gasand a fluid or may be a boiler that is filled with the primary fluid andthat is heated by a heat source. The heat source may be a burner, anelectric resistor, solar energy, and the like.

In another embodiment of the invention, the evaporator itself containsthe heat source. This heat source may be a burner, a reflective mirrorin a solar energy installation or an electric resistor. It may also bean explosion engine, such as an automobile engine, wherein the fluidserves as a coolant for the automobile engine. In case the heat issupplied by such automobile engine, the vapor machine can be connectedto the power output shaft of the engine or may be formed in one and thesame engine block with the explosion engine and thus both the vapormachine and the explosion engine are coupled to the same power outputshaft.

In accordance with another embodiment of the invention, the vapor forcedevice contains more than one vapor machine which are erected one afterthe other in the form of a cascade. In such case, the plurality of vapormachines may be coupled to each other in closed circuits whereby thefluid in the fluid circuit for the second or subsequent vapor machine isheated by the first or preceding vapor machine and/or by the fluidrunning through it. Again, in such case, the fluids in the successorcircuits may be different, such as each having a different temperaturefunction.

Thus, it is an object of the present invention to provide a vapor forceengine that has a primary fluid therein that is heated by the waste heatfrom an explosion engine such as an automobile engine that has a fluidcirculating therethrough to cool the explosion engine.

It is also an object of the present invention to provide an explosionengine and a vapor force engine within a common housing and both havingpistons coupled to a common output drive shaft, the explosion enginebeing cooled by a first fluid that is heated to a first temperature andthe vapor force engine being driven by a second fluid having avaporizing characteristic that is at a lower temperature than the firsttemperature of the cooling fluid of the explosion engine and that iscoupled in heat transfer relationship to the fluid of the explosionengine to be vaporized and drive the vapor engine.

It is still another object of the present invention to provide a vaporengine and an explosion engine mounted in the same housing and whereinthe vapor engine has a first fluid therein that cools the explosionengine which vaporizes it to drive the vapor engine.

It is still another object of the present invention to mount a pluralityof different vapor machines in the form of a cascade wherein the inputfluid to the first vapor machine is of a temperature and character todrive the pistons therein and the waste temperature of the output fluidthereof is such as to heat a second fluid in the second engine tovaporize it and drive the second vapor piston engine, the wastetemperature of the fluid output from the second vapor engine being suchas to transfer heat to a third fluid in a third vapor piston engine tovaporize the third fluid and drive the third piston engine and thentransmit the fluid output of the third engine back to a heater tovaporize the fluid to begin the cycle all over again.

It is also an object of the present invention to cascade a plurality ofdifferent vapor machines such that they are mounted in separate closedfluid circuits whereby a different fluid flows in each vapor machine andwhich receives its input heat from the waste heat of the preceding vapormachine.

It is an important object of the present invention to utilize avapor-driven piston-type engine that has a first fluid for driving thepistons and a second fluid circulating in a closed loop within theengine in heat transfer relationship with the first fluid to therebyincrease the efficiency of the vapor-drive piston-type engine.

Thus, the invention relates to a vapor force engine containing anvaporizable fluid, an evaporator for vaporizing said fluid, a pistonengine in a closed fluid circuit in which the fluid is vaporized, iscoupled to the piston engine for work, is condensed, and is returned tothe evaporator, the improvement comprising a vapor-driven piston-typeengine having a vapor input and a fluid output, a heat exchanger havingan input and an output coupled to the engine, the heat exchangerreceiving a low temperature fluid from the engine fluid output andgenerating a vaporized fluid for the engine vapor input for driving thepiston engine, an explosion engine cooled by a circulating fluid andserving as a source of heat, a radiator on said explosion engine forcooling the circulating fluid and forming the heat exchanger such thatthe explosion engine circulating fluid is a primary fluid and the lowtemperature fluid for the vapor force engine is a secondary fluid thatflows through the radiator in heat exchange relationship with and isvaporized by the heat of the primary fluid to drive the vapor pistonengine, and the low temperature secondary fluid having an atmosphericevaporation temperature less than 240° C. (464° F.) and havingevaporation characteristics such that high pressure vapor greater than10 bar is provided to the vapor input of the vapor driven piston-typeengine.

The invention also relates to a low temperature vapor force enginecomprising n vapor driven piston-type engines where n≧2, eachvapor-driven piston-type engine having a vapor fluid inlet and a fluidoutlet, a first heat exchanger coupled to the vapor inlet and the outletof a first one of the vapor-driven piston-type engines for receiving thefluid from the fluid outlet of the first one of the vapor-drivenpiston-type engines, a heat source for selectively coupling to the firstheat exchanger to vaporize the fluid therein at a temperature less than180° C. (356° F.) for powering the first one of the vapor-drivenpiston-type engines, a second heat exchanger for receiving the fluidoutput from the first vapor-driven piston-type engine at a temperatureof less than 120° C. (248° F.), the vapor fluid of the secondvapor-driven piston-type engine being coupled to the second heatexchanger for being vaporized at a temperature of less than 120° C.(248° F.) to drive the second vapor-driven piston-type engine, and eachsucceeding vapor-driven piston-type engine having a heat exchangerbetween it and the preceding vapor-driven piston-type engine and havinga vapor fluid therein that will vaporize and drive the succeedingvapor-driven piston-type engine at a temperature less than thetemperature of the output fluid of the preceding vapor-drivenpiston-type engine.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects of the present invention will be more fullyunderstood when taken in conjunction with the following DETAILEDDESCRIPTION OF THE DRAWINGS in which:

FIG. 1 represents a block diagram of a vapor force device according tothe invention;

FIG. 2 represents a block diagram analogous to that in FIG. 1 but withreference to another embodiment of the invention where the heat sourceis an explosion-type engine contained within the same housing as thevapor engine;

FIG. 3 is a block diagram analogous to that in FIGS. 1 and 2 but withreference to yet another embodiment of the invention wherein the fluidthat is vaporized and drives the vapor piston-type engine is the coolingfluid for the explosion-type engine that is housed in a common housingwith the vapor-driven piston-type engine;

FIG. 4 is a block diagram of another embodiment of the present inventionin which the fluid providing the heat sources for a plurality ofcascaded vapor-type engines passes through all of the cascaded engines,entering each engine at one temperature sufficient to vaporize a fluidtherein, exiting the first engine at a temperature to vaporize thesecond fluid in the second engine, exiting the second engine at a stilllower temperature sufficient to vaporize a third fluid in the thirdvapor-type engine and coupling the fluid back to the heater forrevaporizing the fluid and commencing the cycle over;

FIG. 5 is a block diagram of still another embodiment of the inventionin which each vapor machine has its own closed fluid circuit with thetemperature of the output fluid in one engine being sufficient tovaporize a fluid in the succeeding engine and all of which engines arecoupled to a common shaft for providing an output;

FIG. 6 is a schematic diagram of a Baudino vapor-driven piston-typeengine that has two closed fluid circuits and that provides highefficiency;

FIGS. 7A and 7B are block diagram representations using a vapor forcepiston type engine similar to that in FIG. 5 except illustrating thedetails of each vapor engine and Baudino motor all coupled to a commonshaft; and

FIGS. 8, 9, 10 and 11 are each associated with FIG. 7 to explain thepressure and temperature controls thereof.

DETAILED DESCRIPTION OF THE DRAWINGS

The novel vapor force device shown in FIG. 1 includes a vaporizablefluid 1, an evaporator 2 for vaporizing the fluid, a vapor drivenmachine 3 which has pistons driven by the vapor, and a closed fluid path4 in which the evaporator 2 and the vapor machine 3 are mounted for thetransport of the fluid 1. In the closed fluid path 4, upstream of theevaporator 2, is mounted a pump 5. The evaporator 2 may in fact be theradiator of a conventional explosion-type engine 6, such as anautomobile engine, in which the fluid, such as water, flows in closedpath 7 through the heat exchanger or radiator 2 and is pumped by meansof pump 8 back to the explosion engine 6 to continually cool the engine.The heat of the fluid in closed circuit 7 as it exits from the explosionengine 6 to the evaporator 2 may be approximately 240° C. The fluid inthe vapor-driven piston-type engine 3 may be of a type that vaporizesbelow 240° C. such that it will be vaporized by the heat of the liquidin closed path 7 from the explosion engine 6. Thus the invention ischaracterized in that the fluid 1 is not water, but is a medium whichcan be easily evaporated and whose atmospheric evaporation temperatureor boiling temperature is lower than 240° C. and preferably lower than30° C. in circumstances as will be seen hereafter and which hasevaporation characteristics that, even at a low temperature, will enablehigh pressure vapor to be obtained. By "low temperature," it should beunderstood that such low temperatures mean below 240° C., as, forexample, 240° C., 180° C., 120° C. or 60°, respectively, and the term"high pressure" means a pressure equal to or greater than 10 bar, forexample, higher than 20 bar at 120° C., where 1 bar is equal to 1atmosphere.

Fluids which meet these conditions and which are thus suited to be usedin the device are those fluids which are used in cooling installationssuch as fluorohydrocarbons. Suited fluids are, for example,fluorohydrocarbons from the series: trichlorofluoromethane,dichlorodifluormethane, chlordifluoromethane, 1,1-dichloro2,2,2-trifluoroethane, 1,1-dichlor-1-fluorethene,1-chloro-1,1-difluorethene, 1,1,1,2-tetrafluorethene anddifluoromethane. Further, substitutes such as dichlorotrifluoromethane(for example, KLEA F123 of ICI) and tetrafluoroethene (for example, KLEA134a of ICI) are interesting. The first mentioned substance has anatmospheric boiling temperature of 27° C. and a critical temperature of183° C. under a pressure of 36 bar, whereas the last mentioned substancehas a boiling temperature under atmospheric pressure of -26° C. butevaporates at 80° C. under 26.3 bar and at 100° C. even under 39.7 bar.The critical temperature of this substance is 101° C. under a pressureof 40.5 bar.

The vapor is supplied in an analogous manner as steam to a vapor machinewith pistons driven thereby. In the vapor machine 3, there is a pressuredrop. The fluid, under this lower pressure, may have a liquid form andis again pumped to the evaporator 2 by means of the pump 5 as explainedearlier. When the temperature in the evaporator 2 is higher than theevaporation temperature under the given pressure for the vapor machinefluid, a super-heated vapor is obtained and preferably slightlysuper-heated vapor is produced in the evaporator in order to avoidcondensation in the vapor machine 3. Such saturated or super-heatedvapor is already obtained, thanks to the specially selected fluid, atrelatively low temperatures, such that the low-temperature heat sources,which are abundantly available but cannot be easily put to use in anefficient manner, can be used to an advantage. Thus the heat of theexplosion engine 6 in FIG. 1 which is otherwise largely lost to theatmosphere can be put to use.

As stated, in the vapor force device represented in FIG. 1, theevaporator 2 is the heat exchanger or radiator of an explosion engine 6which may be, for example, the radiator of an automobile or othervehicle, which, instead of being cooled with air, is cooled by means ofthe vapor force engine fluid 1 circulating in the closed path 4. Thecooling water which is pumped through the cooling path 7 of the engine 6by means of the pump 8, and which has a temperature of about 80° C.,forms the primary fluid. The fluid which is pumped through the closedpath 4 by means of the pump 5 forms the secondary fluid which is heateduntil it essentially reaches the above-mentioned temperature and therebyevaporates. Downstream of the evaporator 2 is mounted an expansion tank9 in which the evaporated secondary fluid is collected andnon-evaporated fluid is collected. Downstream thereof is mounted apressure regulating valve 10 in the circuit 4. Saturated or preferablysuper-heated vapor under high pressure is obtained in the evaporator 2.As indicated above, when tetrafluoroethene is used as the secondaryfluid 1 in closed circuit 4, a pressure of 26 bar can be obtained at theoutlet of the evaporator 2 at 80° C. The pressure at the inlet of thevapor machine 3 can be set by means of the pressure regulating valve 10,for example, as a function of the pressure in the cylinders of theexplosion engine 6. In this way, the explosion engine 6 and thevapor-driven piston-type engine 3 may be united in one and the sameengine block and may possibly even have a common shaft 18 that can becoupled with some driven unit 20 as illustrated in phantom lines in FIG.1.

As illustrated in FIG. 2, the explosion engine 6 and the vapor-drivenpiston-type engine 3 may be formed in a common housing 17. The operationof the device is similar to that disclosed in FIG. 1 wherein the coolingwater of the explosion engine 6 in closed path 7 passes throughevaporator 2, is condensed and is pumped back to the explosion engine 6by pump 8. The heat given up in the evaporator 2 is applied to the fluid1 which vaporizes in path 4 and is used to drive the vapor-drivenpiston-type engine 3. The condensed fluid at the output of thevapor-driven engine 3 is pumped back to the evaporator 2 by the pump 5where the process is repeated. Again, an expansion tank 9 may be placedin the line.

In the embodiment according to FIG. 3, the evaporator 2 is not theradiator of the explosion engine 6 but is the explosion engine 6 itselfwhich implies that the explosion engine 6 is mounted in the closed fluidpath 4 and the fluid 1 forms the coolant of the explosion engine 6.Thus, as the fluid in closed path 4 is pumped by pump 5 through theexplosion motor 6, it cools explosion engine 6, is vaporized in theprocess and is coupled through expansion tank 9 to pressure valve 10,and thence to the vapor-type engine 3 for driving shaft 18. Both theexplosion-type motor 6 and the vapor-driven piston-type engine 3 may becoupled to the common shaft 18 to drive the shaft 18. A bypass feederloop 11 with a pump 12 and a cooler 16 therein is connected to theexplosion engine 6 so as to cool off the fluid 1 in closed path 4 incase of a default.

FIG. 4 discloses still another embodiment of the novel vapor drivenengine in that the heat for the evaporator 2 is not supplied by anexplosion engine but by a heat source such as a burner 13 that heats theoperating fluid in fluid path 4, by means of a fluid 14 in theevaporator 2 either directly or indirectly, as represented in FIG. 4. Inthe latter case, the evaporator 2 forms a heat exchanger with a boilerfilled with a fluid 14 which forms the primary fluid and a pipe or fluidconduit 15 extending through the boiler and which is part of the fluidpath 4 and through which the operating fluid flows as a secondary fluid.In this case, the fluid in closed path 4 enters the first vapor-drivenpiston-type engine 20 at a temperature, for example, of 180° C. whichwill drive the piston-type engine 20 and vaporize a first fluid in afirst closed system in vapor-driven piston-type engine 20 such asdisclosed in relation to FIGS. 1 and 2. The primary fluid in closedfluid path 4 that exits the first vapor-driven piston-type engine 20 isat approximately 120° C. and is coupled to the second vapor-drivenpiston-type engine 22 in a heat transfer relationship therewith. Asecond fluid flows in a closed fluid path within the second vapor-drivenpiston-type engine 22 that vaporizes at a temperature less than 120° C.and thus drives the second vapor piston engine 22. The primary fluid inthe closed fluid path 4 exits engine 22 at, for example, approximately60° C. and is coupled to the third vapor-driven piston-type engine 24 inheat transfer relationship to a third fluid that flows in a closedinternal fluid path and which vaporizes at a temperature less than 60°C. to drive the vapor-driven piston-type engine 24. All three engines20, 22, and 24 are coupled to a common output shaft 18. The fluid in theclosed fluid path 4 exits the third vapor-driven piston-type engine 24as a liquid which is pumped by pump 5 back to the evaporator 2 where itis revaporized and the system repeats itself.

FIG. 5 is similar to that illustrated in FIG. 4 except the first closedfluid path 4 couples vaporized fluid only to the first vapor-drivenpiston-type engine 20 and exits the heat exchanger 37, shown in phantomlines, at approximately 120° C. It gives up essentially all of its heatto the second fluid in the second engine 22. Thus, the first fluid thenexits heat exchanger 37 as a liquid and is pumped by pump 5 back to theevaporator 2, where the process repeats itself.

The second fluid in second vapor-driven piston-type engine 22 receivesessentially most of the 120° C. heat from the first stage which is at asufficient temperature to vaporize the second fluid and drive the secondengine. However, after expending this energy driving the second engine22, the fluid coupled to the second heat exchanger 36 is atapproximately 60° C. This heat is transferred to the third fluid in thethird vapor-driven piston-type engine 24 where the third fluid isvaporized and drives the third engine 24. The second fluid output fromevaporator 36 condenses to a liquid and is pumped by pump 28 throughclosed fluid path 26 back to evaporator 37 where the process repeatsitself. In like manner, the third fluid in the third vapor-drivenpiston-type engine 24 exits the engine in fluid path 30 at approximately15° C. as a liquid and is forced by pump 32 back to heat exchanger 36where the process again repeats itself. The three vapor-drivenpiston-type engines 20, 22, and 24 are combined in single housing 100and are all coupled to the same drive shaft 18 for driving some device38 such as a generator.

It is to be understood, of course, that the heat source 13 in FIGS. 4and 5 could be solar energy, a hot gas, or any other type of energydesired.

The fluids of the three individual fluid circuits are adapted to thetemperatures required. Thus, as a first fluid, the aforesaidfluoro-hydrocarbon F123 can be used and this fluid can be heated to 180°C. in the heat exchanger. In the first vapor engine 20, this fluid coolsoff to about 120° C. after driving the pistons therein. The second fluidin the second engine 22 is the above-mentioned hydrocarbon F134a whichis heated to about 120° C. and thus evaporates and is used to drive thesecond vapor-driven piston-type engine 22. It cools off to about 60° C.while driving the second vapor-driven piston-type engine 22. This heatcan be transferred to the third vapor engine 24 which is supplied to thethird fluorohydrocarbon, or working fluid, known as R11. This fluidvaporizes at or below 60° C. temperature and drives the third engine 24and exits the third engine 24 at approximately 15° C. In FIG. 4, thefluid out of the third engine 24 is transferred back to the evaporator 2where it is heated again to 180° C. and the cycle is repeated. However,in FIG. 5, each of the separate fluids in the second and third engine 22and 24 are reheated through the radiators or heat transfer devices 36and 37.

If the fluid used as the first fluid is one that can be heated to about240° C. and that cools off to about 180° C. after driving a vapor-drivenpiston-type engine, such vapor piston engine can be placed betweenevaporator 2 and the first vapor piston engine 20 shown in FIGS. 4 and 5and thus a unit is obtained with four temperature levels, which, ofcourse, allows for highly efficient use of the heat. Such embodimentsmake it possible to increase the output of an explosion engine or otherheat source in a simple manner.

An efficient engine that can be used as the vapor-driven piston-typeengines discussed in relation to FIGS. 1-5 is shown in FIG. 6 inschematic form. It is known as the Baudino motor and is patented inFrance where it carries publication number FR 2 588 645-A1 and nationalregistration number 85 15545. (This patent was filed in France on Oct.14, 1985 and was made public on Apr. 17, 1987). The Baudino engine is ananaerobic external combustion engine that uses a combined cycle toco-generate thermal energy (cold, heat) and electrical or mechanicalenergy that can be used for any purpose by means of rational utilizationof any source of heat such as solar energy, coal, gas, and the likewhich is first converted into thermal drive power, then into productiveenergy. The engine is quiet and clean and operates, using any fuel, in aclosed cycle without valves or an ignition system. It can, therefore,meet the strictest requirements of the new markets requiring thecombined use of more than one type of energy such as heat andelectricity, and the like by making use of local fuels which existingengines cannot use.

This makes it an attractive alternative for developing countries whereit can compete with steam turbines and fuel cells as well as a possibleoption for many industrialized countries seeking to conquer new markets.The interchangeability of its components make this simple and toughengine a technology that can be adapted to meet requirements asdifferent as decentralized electricity generation, and surface orunderwater propulsion.

In this system, the movement of the pistons is not caused in the sameway as in conventional engines, as by internal combustion of an air/fuelmixture but by a continuous series of actions performed by two activefluids, a working fluid and a reactivating fluid. These two fluidsoperate in opposite directions of flow inside an enclosure between twoheat sources at different temperatures separated by a two-phaseadiabatic heat exchanger. The system receives heat from the outsideatmosphere or an external source, generates power that can be used inmechanical, electrical or a thermal form, and discharges the residualheat to its cold source.

The system consists of two separate units, an energy conversion unit toconvert the energy used to thermal energy and a fluid tight condensationdrive power unit to convert the thermal energy to thermal mechanical orthermal electric energy. The thermal energy conversion chambers adaptedto the energy source used such as solar, oils, waste matter, gas, andthe like. This energy source can be used continuously since the movementof the pistons is not connected to the injection and the discharge ofcombustion gases and this considerably reduces the quantity of harmfulgases such as nitrogen oxides, carbon monoxide, and the like dischargedto the outside atmosphere by conventional engines. The condensationchamber contains the engine block and the driven systems includingcompressors, pumps, AC generators, fluid tight enclosed fluid/vaporcirculation systems and thermal reactivation circuits. The engine blockconsists of a number of adjacent cylinders such as three, each of whichcontains a piston to transmit mechanical power to the drive shaft. Thecompression assembly consists of a number of radially arrangedcylinders, three for example, each of which contains a piston that isthermodynamically coordinated with the adiabatic heat exchanger and thatis integral with the reactivation thermal coils. This ensures optimalcoupling of the engine-compressor assembly and operation at constanttorque appropriate to the load. The job of the turbine pump is to ensureconstant flow rate circulation and recombination of the working fluid.

Considering now FIG. 6, under the effect of the heat it receives, theworking fluid in the high-pressure evaporator 41, evaporates thusincreasing its pressure and the vaporized fluid can then be used todrive the engine pistons 42 cyclically in a well-known manner. Anexternal heat source 40 may provide the heat to the working fluid in thecontainer or high-pressure evaporator 41. The evaporated fluid or gasexiting from the pistons 42 is discharged to axial pump 49 and heatexchanger 39 where it transfers a part of its heat in closed circulationto the reactivation fluid in fluid path 44. Heat exchangers 39 and 46are integrally formed as one unit. Thus, gas exiting piston 42 flowsthrough one part 39 in one direction and through the other part 46 inthe other direction. It is then discharged to the cold source 43 whereit condenses and then passes through turbine pump 51 to the heatexchanger 46 (in the opposite direction than in heat exchanger 39) andreturns to its starting point in the closed container 41 for a newcycle. Thus it should be understood that the heat exchangers 39 and 46are part of an integral unit through which the gas from the pistons 42passes in the first direction and then comes back through in theopposite direction as a fluid through the same heat exchange unit. Thusthe fluid in the high-pressure tank 41, at equal mass, occupies agreater volume in its vapor phase than in its liquid phase. Thedifference in volume is converted to power that can be used by the driveshaft 48 and its latent heat is at least partially utilized by thethermal reactivation loop fluid path 44. From the heat exchanger 39, thethermal reactivation fluid is coupled in fluid path 44 to a series ofcompressors 45 and hence by temperature increases, to the adiabatic heatexchanger 46.

The discharge of the decompressed active fluid from the engine blockcylinders 42 (the decompression is not interrupted, but the fluid isdecompressed to equilibrium), and the forced recompression of the fluidin part of the heat exchanger 46, through which the reactivation fluidlow pressure circuit 44 passes, is caused by the axial pump 49 which isintegral with the turbine 50. The turbine 50, which is mechanicallycoupled to the drive shaft 48, is partly driven by decompression of thecompressed reactivation fluid at 46 and this compensates for aconsiderable proportion of the power spent on cyclical recombination ofthe thermal energy. Depending on the type of application, or the type ofcombustion chamber used to heat the active engine fluid, the thermalreactivation loop is used either to transfer the heat of the workingfluid from the inside of the system to the outside or vice versa.

The choice of fluids determine the design technology of the engine andintegrate the following parameters: temperature, pressure, heat exchangesurface, need for sharp decompression that does not require over-heatingat the engine cylinder inputs, and in particular the thermal loops. Intheoretical terms, an organic fluid containing fluoro, such as fluorinetFC75 in the thermal drive loop, would combine well with freon R11 in thereactivation loop.

The use of the Baudino motor in a multi-stage vapor-powered engine isillustrated in FIG. 7A and FIG. 7B. The engine 52 comprises three stages54, 56, and 58, with each stage formed of a Baudino motor. It should berealized that each Baudino motor is represented by that motor disclosedin FIG. 6 and is shown in FIG. 7A and 7B with the engine pistonsseparated therefrom in order to show the connections between the enginepistons and the remainder of the Baudino motor. Thus in the first stage,the Baudino motor 54 and the engine pistons 53 are within the samehousing as represented by the dashed line 51 surrounding the enginepistons 53 and extending from the Baudino motor 54. In like manner,engine pistons 55 are an integral part of the Baudino motor 56 asillustrated by the dashed line 61 surrounding the engine pistons 55. Inlike manner, the engine pistons 57 in the third stage are formed in thesame housing as the Baudino motor 58 as indicated by the dashed line 63surrounding both of them.

The heat to drive the process of this engine is shown derived from asource such as a boiler 60 with a burner system 62 to provide the heat.A fuel such as gas in line 65 is coupled through a control valve 66 tothe burner system 62. The boiler feed liquid in line 64 in boiler 60 isheated by the burner system 62 and vaporized. A pump 68 pumps the liquidfluid into the line 64 into boiler 60. A liquid control valve 70 is inparallel with the pump 68, so that, as will be described later, if thevalve 70 is opened, the pump 68 is essentially disabled to stop pumpingthe fluid as needed.

A liquid level sensor 72 detects the level of the liquid in theexpansion tank 73 and the boiler 60. The vaporized liquid is coupled toline 75, where a pressure sensor 74 and a temperature sensor 76 give aconstant indication of the pressure and temperature of the vapor in theline 75. Thus, as can be seen in FIG. 8, a computer may be used tocontrol the operation of the various valves and pumps based upon theliquid level, pressure, and temperature indicated by the sensors 72, 74and 76. Thus, at 82 in FIG. 8, the computer fluid level indicatorcontroller receives the liquid level indication from sensor 72 and sumsthat signal at 88 with the pressure signal received by the pressureindicator controller 84 that is derived from the pressure sensor 74. Theresult of the summation at 88 is used to control the level control valve70 that bypasses the fluid pump 68 as described earlier. Thus, if thelevel becomes too high and/or the pressure increases beyond presetlimits, the liquid control valve 70 is opened the proper amount andcontrols the amount of fluid that pump 68 can continue to supply to theboiler 60. In like manner, as can be seen at step 86 in FIG. 8, thetemperature indicator or controller receives the temperature signalproduced by the temperature sensor 76 and is used by the computerthrough auto selector 85, in conjunction with the pressure indication atstep 84 to control the pressure control valve 66 that regulates theamount of gas in line 65 being fed to the burner assembly 62. Thus ifthe pressure and/or the temperature becomes too high, the amount of gasbeing fed to the boiler to produce that temperature is decreased bypartially closing control valve 66. All of these controls by computerare old and well-known in the art and the operation and control of suchvalves based upon temperature and pressure signals is not new in and ofitself.

The vaporized fluid in line 75 is coupled to a manually adjustable valve78 which may be similar to a needle valve on a carburetor to allowminimum speed control of the motor. Speed control valve 80 is manuallycontrolled, such as by hand throttle or a foot pedal, but of course,could be controlled by a computer, to provide the amount of vapornecessary to drive engine pistons 53 of the first stage 54 of theBaudino motor. Thus the vapor begins to drive the pistons 53 of thefirst Baudino motor 54 that begin to rotate shaft 102 which is commonlycoupled to all of the stages. The output vapor from pistons 53 on line89 is used in the Baudino motor 54 as has been explained previously withrespect to FIG. 6 and will not be repeated here. The vapor output fromthe Baudino motor 54 on line 90 is coupled to a preheater 92 which is aheat exchanger that also receives the fluid on line 94 from the secondBaudino motor 56 prior to its being coupled to engine pistons 53 as thecooling fluid. In addition, the vapor in line 90 that passes throughpreheater 92 also passes through a cooler 96 by giving up its remainingheat to the fluid 98 from the third stage Baudino motor 58. Thus, thefluid in line 90 gives up its heat to the fluid in line 98 and is cooleditself to a liquid in line 67 where it is coupled back to pump 68 andthe cycle then repeats itself. Thus, as can be seen in FIG. 9, themanual control 104 (or a computer-controlled signal) controls the speedcontrol valve 80 to allow more or less vapor to the piston engine 53 toregulate the engine speed.

The pressure and temperature of the vapor in line 75 entering pistonengine 53 is measured by sensors 108 and 110, respectively. Further, abypass valve 112, when opened, allows the vapor to pass through conduit113 to the cooler 96 for return to pump 68. Thus, referring to FIG. 9,when the pressure and/or temperature as indicated by sensors 108 and 110are too high or outside normal limits, the computer, as shown in FIG. 9,through pressure and temperature indicator controllers 114 and 116, usesthe sensor signals indicating abnormal pressure and temperature to drivea controller 118 to control the valves 106 and 112. If valve 106 isopened, the vapor can bypass the engine pistons 53 and go directly tothe remainder of the Baudino motor 54 at a higher temperature. If thepressure and temperature are such that they must be reduced, then valve112 is opened to bypass the entire group of Baudino motors and to couplea predetermined portion of the vapor back through cooler 96 where it iscondensed to a liquid in line 67 and coupled back to pump 68. Thus, notonly the pressure and temperature of the vapor coupled to the Baudinomotor piston 53 are controlled but also the pistons 53 can be bypassedentirely or a portion of the vapor can be coupled back to the cooler 96to preheat the fluid from the second and third stages in conduits 94 and98.

Further, the temperature at preheater 92 is monitored by sensor 120while the temperature at cooler (or preheater) 96 is monitored bytemperature sensor 122. If the temperature at preheater 92 is below apredetermined temperature as determined by sensor 120, then, referringagain to FIG. 9, the computer utilizes that sensor signal throughtemperature indicator controller 124, and an automatic selector 128 tocontrol PC valve 106 and bypass the engine pistons 53 and couple thevaporized fluid directly to the Baudino motor 54, thus increasing thetemperature on the output line 90. In like manner, if the temperature ofcooler 96 is below a predetermined level, as determined by sensor 122,then, referring again to FIG. 9, the computer through temperatureindicator controller 126 utilizes that information to operate automaticselector 128 and control bypass valve 112 to allow more of the vaporizedfluid to be conducted directly to the cooler 96 by bypassing the Baudinomotor piston engine 53 entirely and providing more heat to the thirdstage engine 58 as will be explained hereafter.

In the fluid return line 94 from the second stage Baudino motor 56,there is a pump 136 for pumping the fluid back to the first stage enginepistons 53. The engine pistons 53 serve as the heat source for the fluidfor the second stage Baudino motor 56. A fluid level sensor 130 on thepiston engine 53 gives an indication if there is a fluid buildup in thepiston engine 53. If so, referring again to FIG. 9, the signal generatedby the fluid level sensor 130 is used by the computer through levelindicator controller 132 to control a valve 134 that bypasses pump 136to control the amount of fluid being pumped in line 94 back to the heatsource or piston engine 53.

Considering the second stage, the fluid pumped by pump 136 (in FIG. 7B)from the second stage Baudino motor 56 passes through the preheater 92(in FIG. 7A), where, as indicated earlier, it receives heat remaining inthe fluid output from the first stage Baudino motor 54 on line 90 and isthus preheated. It is then coupled to the engine piston unit 53 of stage1 where it serves as the coolant for stage 1 and, in the process, isvaporized and is output from piston engine 53 in conduit 138 to thesecond stage engine pistons 55 in FIG. 7B. Again, the temperature andpressure of the vapor in conduit 138 is detected by sensors 140 and 142.If either the pressure and/or the temperature exceeds predeterminedlimits, then referring to FIG. 10, the computer, through pressure andtemperature indicator controllers 146 and 148, utilizes the temperatureand pressure indications from sensors 140 and 142 to control anautomatic selector 150 that controls PC valve 144. PC valve 144 is apressure control valve that bypasses the engine pistons 55 and couplesthe fluid directly into the Baudino motor 56 of the second stage. Thusagain the pressure and temperature of the fluid that is being suppliedto the engine pistons 55 is controlled. Again, the vapor output frompiston engine 55 in conduit 152 is coupled to Baudino motor 56 whichfunctions as described previously in reference to FIG. 6. The fluidoutput of the Baudino motor 56 on line 154 is coupled to a pre-heater156 and to a cooler (or pre-heater) 158 where the fluid is condensed inconduit 160 and is coupled back to pump 136 for recycling through thesecond stage as described previously. Again, temperature sensors 162 and164 are provided for the preheater 156 and the cooler 158, respectively.Should these temperatures be indicated to be improper, the computer,using temperature indicator and controller 166 and 168 in FIG. 10, againusing automatic selector 170, controls bypass PC valve 144 to allow thevapor to bypass the engine pistons 55 and be supplied directly to theBaudino motor 56 in the second stage. Thus the output of the secondstage Baudino motor 56 on line 154 would then have an increasedtemperature for supplying to the preheater 156 and the cooler 158.

It will be noted that the third stage of Baudino motor 58 illustratesthe details thereof and its connection to the piston engine 63 in thesame manner as illustrated in FIG. 6. As indicated earlier, each of theBaudino motors 54 and 56 are likewise constructed. It will be noted thatinternal pump 172 in Baudino motor 58 in the third stage is driven bythe shaft 102. Thus in like manner the pump 68 in the first stage andpump 136 in the second stage may be part of the Baudino motors 54 and56, respectively, in the same manner as illustrated in Baudino motor 58in the third stage. However, the pumps 68 and 136 are shown external toBaudino motors 54 and 56 for ease of explanation. Pump 172 pumps thefluid through line 176 out of the Baudino motor 58 to the cooler 158 inthe second stage where it picks up some heat and also helps to condensethe output vapor from the second stage. It continues to the cooler 96 inthe first stage where it does the same thing and picks up additionalheat. It then returns in conduit 180 to preheater 156 in the secondstage where it picks up more heat from the output vapor of the secondstage in conduit 154 and then is fed into the piston engine 55 as thecoolant therefor. As it is cooling the pistons 55, it absorbs heat andis vaporized and exits the piston engine 55 in conduit 182 where itreturns to the input of the piston engine 63 of Baudino motor 58. Thereit drives the pistons and then passes through the Baudino motor 58 asexplained earlier and repeats the process.

It will be noted in Baudino motor 58 that a level control valve 174bypasses pump 172. A fluid level sensor indicator 184 is associated withthe second stage piston engine 55 thus providing an indication when apredetermined fluid level is reached in piston engine 55. Then,referring to FIG. 10, the signal from fluid level sensor indicator 184is utilized by the computer and level indication controller 190 tocontrol the fluid level control valve 174 in Baudino motor 58 to openthe valve 174 and reduce the amount of fluid being pumped by pump 172.Thus control can be maintained of the fluid level in the piston engine55 of the second stage.

It will also be noted that at the output of the piston engine 55 of thesecond stage, that there is a pressure sensor 186 and a temperaturesensor 188. Referring now to FIG. 11, a pressure indicator controller190 is controlled by the computer to operate an auto selector control194 to control the pressure control valve 144 at the input to the secondstage piston engine 55 so as to bypass the engine 55 if necessary andthus increase the temperature of the fluid that is in heat transferrelationship with the fluid from the third stage in the preheater 156and the cooler 158. Further, fluid level control sensor 196 can beattached to the piston engine 57 of the third stage and referring toFIG. 11, the level indicator controller 198, under control of thecomputer, may operate the level control valve 174 in the Baudino motor58 to bypass pump 172 and thus maintain the proper fluid level in thethird stage piston engine 63.

It will be noted that gear boxes 200 and 202 interconnect the shaft 102of the three stages. Thus gear box 200 connects stages one and two withthe shaft 102 while gear box 202 couples the second stage to the thirdstage with the output shaft 102. The gear boxes are well-known and haveinner and outer toothed wheels in engagement with each other and arespective shaft portion. This will enable forces on the shaft from thethree stages to be balanced even if the speed of the three units isdifferent. When the computer controls the three stages to achievesubstantially the same speed, the inner and outer toothed wheels willsimply rotate together.

A description of the operation of the multi-stage vapor-powered engine52 shown in FIG. 7A and FIG. 7B is now discussed. During start-up, theboiler 60 and burner 62 are started with a signal that initiates thefollowing sequence: first, the liquid supply pump 68 is activated andthe level of the liquid in the boiler 60 is controlled based on theoutput signal from level sensor 72 as indicated previously. At the sametime, the pilot light of the burner system 62 opens a safety valve in awell-known manner and allows fuel in line 65 to flow through pressurecontrol valve 66 and is ignited by burner 62. The burner 62 is open to amaximum flow rate which heats up the system and brings it to therequired pressure. To commence operation, a starter motor 204 may beconnected to and rotate shaft 102 to begin circulating the fluid to thevarious stages by the pumps 68 in the first stage, 136 in the secondstage, and 172 in the third stage. It will be recalled, as statedearlier, that pumps 68 and 136 in the first and second stages,respectively, can be a part of the Baudino motor as illustrated by pump172 in the third stage Baudino motor 58. When pressure indicator 74 andtemperature indicator 76 in conduit 75 to the first stage piston engine53 indicate that the input to the system is brought to the requiredpressure and temperature, the computer controls the gas valve 66 asexplained earlier to maintain the required pressure. Because of theextremely small volume of the liquid in the boiler, this operation takesonly a few seconds.

The motor 52 is operated at a minimum speed by the adjusted needlecontrol valve 78 as explained earlier and the desired speed iscontrolled by operation of the manual control valve 80 to drive stageone. To have a fast balanced system, stages two and three can beactivated quickly by controlling bypass valves 106 in the first stageand 144 in the second stage to cause a predetermined amount of thevaporized fluid to be transferred immediately to the second and thirdstages. These bypass valves 106 and 144 are controlled by the computerthrough the pressure controllers 106 in FIG. 9 and 144 in FIG. 10. Theyare also controlled by temperature controllers 166 in FIG. 10 and 192 inFIG. 11 based on the temperature sensors 122 in the first stage and 158in the second stage at the outlet of coolers 96 and 158, respectively,from stages one and two.

Thus the three pressures applied to stages one, two and three asindicated by associated pressure sensors are based on the pressures andtemperatures of the inputs and outputs of each stage. The pressurecontrol valves 106, 112 and 144 are controlled by the computer to bringthe system quickly into balance. Once the stages are in balance, thenthese valves will be either closed or operated at reduced positionsbased on the computer control.

The three stages are individually powered units and the forces appliedto the shaft are required to be balanced. Therefore the speed of thethree units may be different and yet mechanically changed by the innerand outer toothed wheels illustrated by gear boxes 200 and 202 in FIG.7A and FIG. 7B. By mechanically allowing the toothed wheels to rotatewith respect to each other in a well-known manner, the forces applied toshaft 102 are balanced. The pressures on the pistons and in the lines asdetermined by pressure sensors as indicated, indicate the measurementsof the power on each shaft from each stage. A computer compares thesepower measurements in a well-known manner and the heat flux from onestage to another is varied by the computer as indicated to regulate thespeed of shaft rotation of the three stages.

Because, as indicated earlier, each of the Baudino motors 54, 56, and 58utilize a different fluid that boils at a temperature less than theoutput temperature of the preceding stage, stage 2 is receiving wasteenergy from stage 1 and stage 3 is receiving waste energy from stage 2.In the case of needed energy in either stage 2 or stage 3 to balance thepower, stages 2 and 3 are able to receive additional energy through thebypass valves 106 and 144 from stage 1 or stage 2 thus controlling thetransfer temperature in the preheaters 92 and 156 and coolers 96 and158. The computer controls the overall heat balance to obtain theoptimum working conditions and the cooling temperatures in coolers 96and 158. The coolers of stage 1 and stage 2, 96 and 158 respectively,are designed such that the maximum heat flux during heat transferperiods is taken into consideration. Of course the coolers may beoversized to avoid cavitation in the pumps and to safely cool theliquid.

All of the controllers in the systems shown in FIGS. 8, 9, 10 and 11 bythe numerals 82, 84, 86, 104, 114, 116, 124, 126, 132, 146, 148, 166,168, 190, 191, 192 and 198 are all proportional-integral controllersthat are well-known in the art and are such that when the enginefunctions are noted to have a certain deviation from a set point asindicated by measurement signals, the integral function is eliminated.The integral function comes back into service whenever it is necessaryto avoid overshooting in control as is well-known in the prior art.

To increase or decrease the power or speed of the motor, the main supplyvalve 66 for the fuel is open to stage 1 and boiler 60. Becausetemperature and pressure are always kept constant at the output of theboiler 60, quick acceleration or heavy tracking at low speed is possiblewithout perturbation of the combustion. Thus the pressure andtemperature of the fluid from the boiler 60 are controlled separatelyfrom the pressure and temperature that are generated by each of thepiston engines 53 and 55 for the three stage motors. The temperaturecontrollers are in auto select operation to limit the temperature of thevapors in the coolers and/or preheaters.

Thus the present invention relates to a vapor engine that has multiplestages but may be formed in a single block. Each stage has it ownseparate vapor power source and the fluids in each stage are differentand have different heat/temperature characteristics. In operation, afirst fluid passing through the first stage itself is heated by a boilerto a first temperature and passes through the first engine stage. Thefirst fluid is pumped back to the boiler by a pump. Stage 1 drives anengine shaft. Excess temperature of the first stage is passed to acooling fluid from the second stage. The cooling fluid of the secondstage is a second different fluid which, at a second lower temperature,uses the waste heat of the first stage to drive pistons which are alsocoupled to the same shaft as the first stage. The second fluid of thesecond stage passes through an internal heat exchanger and is pumpedback to the first stage for recirculation. A third engine stage has athird different fluid which passes through the heat exchangers of boththe first and second stages where it is heated to a third lowertemperature than the second stage waste heat and then drives the commonshaft after which the third fluid is pumped back to the second stage tobe recirculated. The three stages may be mounted one after another in acascade form and be constructed in one unitary engine block. The fluidsin the three circuits are all different and are adapted to vaporize atthe temperature required by those particular engine stages.Fluorohydrocarbons may be employed as the fluids.

While the invention has been described in connection with a preferredembodiment, it is not intended to limit the scope of the invention tothe particular forms set forth, but, on the contrary, it is intended tocover such alternatives, modifications, and equivalents as may beincluded within the spirit and scope of the invention as defined by theappended claims.

We claim:
 1. A low-temperature vapor force engine comprising:at leastthree vapor-driven piston-type engines, each of said engines having avapor fluid inlet and a fluid outlet; a first heat exchanger coupled tothe vapor inlet and the outlet of a first one of said vapor-drivenpiston-type engines for receiving the fluid from said fluid outlet ofsaid first one of said vapor-driven piston-type engines; an externalheat source for selectively coupling to said heat exchanger to vaporizethe fluid therein at a temperature of less than 180° C. (356° F.) forpowering said first one of said vapor-driven piston-type engines; asecond heat exchanger for receiving the fluid output from said firstvapor-driven piston-type engine at a temperature of less than 120° C.(248° F.); a vapor fluid of said second vapor-driven piston-type enginebeing coupled to said second heat exchanger for being vaporized at atemperature less than 120° C. (248° F.) to drive said secondvapor-driven piston-type engine; and each succeeding vapor-drivenpiston-type engine having a heat exchanger between it and the precedingvapor-driven piston-type engine and having a vapor fluid therein thatwill vaporize and drive said succeeding vapor-driven piston-type engineat a temperature less than the temperature of the output fluid of thepreceding vapor-driven piston-type engine.
 2. A low-temperature vaporforce engine comprising:three vapor-driven piston-type engines, each ofsaid engines having a vapor fluid inlet and a fluid outlet; the firstone of said engines having a first fluid thereon that is vaporized atless than 180° C. (356° F.) at its vapor fluid inlet and generates wastefluid heat at its fluid outlet of less than 120° C. (248° F.); thesecond one of said engines having a second different fluid therein thatis vaporized at less than 120° C. (248° F.) at its vapor fluid inlet andgenerates waste fluid heat at its fluid output of less than 60° C. (140°F.); the third one of said engine having a third different fluid thereinthat is vaporized at less than the 60° C. (140° F.) of the fluid at thefluid outlet of the second engine; a heat exchanger between each twosucceeding ones of said three engines such that the temperature of thewaste heat from the preceding engine serves as an external heat sourcefor and vaporizes the different fluid in the succeeding engine therebydriving each of said engines; and a heat source coupled between saidvapor fluid inlet and said fluid outlet of said first engine forvaporizing said first fluid and driving said first engine.